JSOM Check out and check in a Page in sharepoint.

function checkOut(){
        var ctx = SP.ClientContext.get_current();
        var page = ctx.get_web().getFileByServerRelativeUrl(window.location.pathname);
        page.checkOut();
        ctx.load(page);
        ctx.executeQueryAsync(Function.createDelegate(this, checkOut_Success),
                                            Function.createDelegate(this, checkOut_Fail));
}
function checkOut_Success(sender, args){

alert("Checked Out");
}
function checkOut_Fail(sender, args){

   alert("Fail checkout");
}

function checkIn(){
         var ctx = SP.ClientContext.get_current();
        var web = ctx.get_web();
        var page = web.getFileByServerRelativeUrl(window.location.pathname);    
        page.checkIn();
        page.publish();
        ctx.executeQueryAsync(Function.createDelegate(this, checkIn_Success),
                                            Function.createDelegate(this, checkIn_Fail));
}
function checkIn_Success(sender, args){      
    alert(" checked in ");
}
function checkIn_Fail(sender, args){

   
    alert("Fail  checked in "+args.message);
}